This application relates generally to gas turbine engines and, more particularly, to methods and apparatus for assembling gas turbine engine rotor assemblies.
At least some known gas turbine engines include a compressor for compressing air which is mixed with a fuel and channeled to a combustor wherein the mixture is ignited within a combustion chamber for generating hot combustion gases. The hot combustion gases are channeled downstream to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work to propel an aircraft in flight or to power a load, such as an electrical generator.
Known compressors include a rotor assembly that includes at least one row of circumferentially spaced rotor blades. Each rotor blade includes an airfoil that includes a pressure side, and a suction side connected together at leading and trailing edges. Each airfoil extends radially outward from a rotor blade platform. Each rotor blade also includes a dovetail that extends radially inward from a shank coupled to the platform. The dovetail is used to mount the rotor blade within the rotor assembly to a rotor disk or spool. Known shanks are hollow and include a convex sidewall and a concave sidewall.
During operation, because of continued exposure to high temperatures and stresses, at least some known rotor blades may be subjected to low cycle fatigue. More specifically, at least some known rotor blades may be susceptible to low cycle fatigue and/or creep along a pressure side of the platform and/or at the filet radius extending between the platform and the airfoil.
To facilitate reducing the effects of the high temperatures, at least some known rotor blades include a cooling opening formed within the shank. More specifically, within at least some known shanks the cooling opening extends through the concave sidewall for providing impingement cooling air to the platform. In other known shanks, the cooling opening extends through shank convex sidewall. However, within known rotor blades, such cooling openings may provide only limited cooling to the rotor blades.